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Page 2 of 8 It’s What’s on the Inside that Counts
The Pentium 4 isn’t merely about physical changes -- it hosts a totally new and radical architecture. With the technology inside the Pentium 4, Intel has its first 7th generation processor. AMD was the first to release a 7th generation processor but being the first doesn’t always mean being the best. As history has shown, pioneers don’t always become leaders.
The Pentium 4 integrates the following new features:
Hyper Pipelined Technology
- Very deep pipeline to enable breakthrough clock rates
- Performance scalability and speed headroom for the future
Advanced Dynamic Execution
- Can handle more than 100 instructions in flight
- Enables speculative execution with enhanced branch prediction algorithm
- Offers 128-byte cache lines
- Extends upon basic features found in the P6 architecture
Rapid Execution Engine
- An integer ALU (arithmetic logic unit) clocked at twice the frequency of the Pentium 4 processor, decreasing latency and increasing the throughput of basic integer operations
Execution Trace Cache
- Execution trace Cache feeds fast engine
- Removes IA-32 (Intel Architecture -- 32-bit) decoder from main loop and in turn removes the decoder pipeline latency
Enhanced Floating-Point/Multimedia Unit
- 128-bit Floating-Point/Multimedia execution port
- Separate 128-bit floating-point move and data store port (in addition to the integer store port)
New Streaming SIMD Extensions 2 Instructions
- Offers 144 new instructions -- SIMD double-precision floating-point instructions, SIMD 128-bit integer instructions, conversion instructions between floating-point and integer data, and cacheability instructions.
- Enables excellent performance of next-generation broadband services such as interactive digital TV
A new system bus architecture with high bandwidth for performance headroom
- 3.2GB/sec data transfer rate
- Split transaction, deeply pipelined bus
- 128-byte lines with 64-byte access
Full compatibility with existing IA-32 applications and operating systems
What are all these features and what do they do?
Intel NetBurst Architecture
Intel is pushing its new technology called NetBurst. This is the name given to the set of features that Intel added to the Pentium 4. Throughout this article, there is one thing that you have to keep in mind; the Pentium 4 is ahead of its time and with that and it is in great condition to lead the way in the near future. You may be asking, “Well how does it perform with my current pile of software?” Obviously, the Pentium 4’s performance will be on the high-end of the technological scale, but the real icing on the cake is that when new games and software come out in a few months, they won’t struggle on the processor. All your current software will run perfectly and with ease on the Pentium 4, but while other current processors will lag with new applications, the Pentium 4 will stay right up there.
 NetBurst Architecture
Intel is pushing its NetBurst architecture and a lot of developers are looking at it with inspired eyes. This is rightly so. The Pentium 4 concentrates on your investment life and promises to ensure a long lasting, strong performing product.
This all goes well if developers support the Pentium 4’s exclusive features, but if they don’t, we may be seeing some problems. However, studying Intel’s past reveals a history with strong developer support. From MMX to SSE, developers have flocked to Intel. It definitely shouldn’t have trouble winning votes for the Pentium 4 and becoming a leader. I can’t say the same for the current situation down in Florida. Hyper Pipelined Technology
Intel’s strategy is a sure fire one -- obtain the fastest processing speeds possible. Intel has used one method to do so leveraging new architectural improvements in the Pentium 4. But then again, technical improvements aren’t going to sell without the hype of GHz power is it? Definitely not.
Right now, Intel surely has to be proud of its tremendous success with the Pentium III. After all, that processor saw so many different speeds and sold pretty darn well. So why couldn’t Intel just bump up speeds on the Pentium III to 1.5GHz or something? The answer takes a little explaining to do -- you need to have more pipes!
 P6 Super Pipeline vs. Pentium 4 Hyper Pipeline
Above is a diagram comparing the original execution pipeline of the Pentium Pro. A pipeline is like an assembly line. Chunks of data pass through the pipeline going through stages. In the P6 architecture, there were 10 stages. In Intel’s new Hyper Pipeline Technology, there are 20 stages. What does this all have to do with increasing processor speed? Well, to increase processor speed, you have to make it do less per clock cycle, that is, per Hz. You may now be asking, “Well doesn’t a 10-stage pipeline have to do less work than a 20-stage pipeline?” The quick answer is no, it doesn’t.
 Look at all those pipes!
What I mean by doing less work is that since the pipeline is longer, it will also take longer for instructions to be processed all the way to the end of the pipeline. With the P6 pipeline, the processor could do, let’s say 3 stages per clock cycle. Now let’s say with Hyper Pipeline, the Pentium 4 also can do 3 stages per cycle. The Pentium 4 now does 3 out of 20 whereas the P6 did 3 out of 10 -- 50% work per clock cycle. If you design a processor to do less per clock cycle, it is able to reach much higher speeds than processors that do more per clock cycle. This is the reason why Intel released the Pentium 4 at such high speeds. If they were releasing another Pentium III processor, it would likely be only around 1.2GHz. Obviously Intel has the capabilities to create multi GHz processors -- evident with the Pentium 4 -- it's just that the architecture has reached its limits.
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